export enum TweenType {
    linear = 0, 
    quadIn, quadOut, quadInOut, 
    cubicIn, cubicOut, cubicInOut, 
    quartIn, quartOut, quartInOut, 
    sineIn, sineOut, sineInOut, 
    expoIn, expoOut, expoInOut, 
    elasticIn, elasticOut, elasticInOut, 
    backIn, backOut, backInOut, 
    bounceIn, bounceOut, bounceInOut
}